Foundations

Rebuilding a Chimney Top

Stainless anchors and pressure-injected grout form a strong bond with the original masonry

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Back in 2006, I took on an unusual chimney-repair job in Chestnut Hill, a well-to-do urban neighborhood on the outskirts of Boston. When I first met with the new owner, he called the 1929 brick home's four decoratively corbeled chimneys its "crown jewels." Certainly, viewed from the ground, they were impressive. The two largest measured 9 feet by 3 feet 6 inches in plan and towered 22 feet above the roof line. The two smaller ones were 4 feet square and stood 14 feet above the roof.

I was hired to inspect the chimneys for structural integrity and conduct any necessary repairs. Indoors, the fireplaces showed significant deterioration. Firebrick hadn't been used to build the fireboxes, and water had infiltrated all the way down each chimney, carrying leached salts that had crystallized and expanded within the bricks,...